JP4395583B2 - Ni-Cr-W alloy alloy filler metal for welding - Google Patents
Ni-Cr-W alloy alloy filler metal for welding Download PDFInfo
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- JP4395583B2 JP4395583B2 JP14211699A JP14211699A JP4395583B2 JP 4395583 B2 JP4395583 B2 JP 4395583B2 JP 14211699 A JP14211699 A JP 14211699A JP 14211699 A JP14211699 A JP 14211699A JP 4395583 B2 JP4395583 B2 JP 4395583B2
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3033—Ni as the principal constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3033—Ni as the principal constituent
- B23K35/304—Ni as the principal constituent with Cr as the next major constituent
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Description
【０００１】
【産業上の利用分野】
本発明は、高温ガス炉高温部構造物、ガスタービンなどに用いられる高温強度、耐食性に優れたＮｉ−Ｃｒ−Ｗ系合金の溶接用溶加材に関するものである。
【０００２】
【従来の技術】
従来、高温ガス炉高温部構造物、ガスタービンなどに用いられる超耐熱材料として、Ｎｉ−Ｃｒ−Ｗ系合金、Ｎｉ−Ｃｒ−Ｗ−Ｍｏ系合金などが開発されてきた。これらの合金は１０００℃付近の高温で使用されるため、高温クリープ強度、耐食性に優れていることが要求される。
【０００３】
このような要求から、たとえば、特開昭５１−２９３１６、特公昭５４−３３２１２、特公平５−４７６１２に開示されているようなＷやＭｏで強化されたＮｉ−Ｃｒ合金が提案されている。これらの合金を用いて、構造物を製作するためには、溶接が用いられる。さらに、このような構造物は高温で長時間使用されることから、溶接部に対しても高温クリープ強度が必要とされる。
【０００４】
特開昭５１−２９３１６には、Ｎｉ−Ｃｒ−Ｗ系合金、Ｎｉ−Ｃｒ−Ｗ−Ｍｏ系合金による溶接構造物を作るための溶接用耐熱合金が開示されているが、Ｗ量が３〜２０％の合金に対して、溶接割れを起こさないような組成範囲を示しているにとどまっている。ＮＩ−Ｃｒ−Ｗ系の合金は溶接割れ感受性が非常に高く、母材と全く同じ化学組成の合金を溶加材に用いた場合、溶接割れを起こし、健全な溶接構造物を作ることは困難である。また、溶接部の高温クリープ強度が母材なみに高いことが高温構造物の健全性を確保する上で重要であるが、Ｎｉ−Ｃｒ−Ｗ系の合金の場合、溶接ワイヤーに加工が可能で、溶接性に優れ、かつ溶接部の高温クリープ強度も母材と同程度に優れた溶加材を開発するには至っていない。
【０００５】
【発明が解決しようとする課題】
本発明の目的は、溶接割れ感受性の高いＮｉ−Ｃｒ−Ｗ系合金に対して、熱間加工性に優れていてワイヤーに加工が可能であるとともに溶接性に優れ、かつ溶接部の高温クリープ強度が母材と同程度に優れた溶接用溶加材を提供することにある。
【０００６】
【課題を解決するための手段】
本発明は
Ｃ：０．０５％以下
Ｍｎ：０．１％以下
Ｓｉ：０．１％以下
（ただし、Ｍｎ＋Ｓｉ＝０．１％以下）
Ｃｒ：１７〜２０％
Ｗ ：２０〜２３％
（ただし、Ｃｒ＋Ｗ＝３９〜４３％）
Ｔｉ：０．０２〜０．１％
Ｚｒ：０．０３％以下
Ｙ ：０．０１５％以下
Ｂ ：０．０００３〜０．０１％
Ａｌ：０．１％以下
Ｍｇ：０．０５％以下
Ｎｂ：０．０６％以下
（ただし、１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙ＝０．３％以下）
を含有し、残りがＮｉおよび不可避不純物からなる組成（以上、質量％）を有するＮｉ−Ｃｒ−Ｗ系合金の溶接用溶加材である。
【０００７】
【発明の実施の形態】
本発明の溶接用溶加材は、特公平５−４７６１２で発明したＮｉ−Ｃｒ−Ｗ系超耐熱合金のうち、Ｎｉ−１８．５％Ｃｒ−２１％Ｗ合金を骨格組成とした母材合金に対し、合金中に含まれる微量元素の量を調整することにより、溶接用ワイヤーに加工可能であるとともに溶接性が優れ、かつ溶接部の高温クリープ強度を母材なみとすることができる。以下に、本発明の溶接用溶加材の各成分添加理由および組成限定理由について述べる。
【０００８】
Ｃは合金を製造する上で熱間加工性を向上させる元素であり、一般的には高温クリープ強度を向上させる元素である。しかしながら、Ｎｉ−Ｃｒ−Ｗ系合金では、使用温度が高温であるため、クリープ強度はＣの量にはあまり依存せず、また使用中にＣの合金外への移行が起こる場合がある。さらに、Ｃ量が多いと、脆い炭化物の析出により、時効脆化感受性が高くなる。そのため、Ｃ量は低く抑えることとし、０．０５％以下を含有することとした。好ましい含有量は０．０１〜０．０４％である。
【０００９】
Ｍｎ及びＳｉは合金の溶製時に脱酸作用があり、さらに耐食性向上に有効であるが、熱間加工性、クリープ強度を低下させる。Ｎｉ−Ｃｒ−Ｗ系合金において熱間加工性及びクリープ強度を確保するため、Ｍｎ、Ｓｉ単独ではともに０．１％以下に、両元素が同時に存在する場合には、その和を０．１％以下に限定した。
【００１０】
Ｃｒは溶接金属の耐食性、高温クリープ強度の確保のために必要であるが、過剰に添加すると溶接ワイヤーへの加工性を損なう。本発明では、特公平５−４７６１２で発明したＣｒ量１６〜２８％の母材合金のうち、耐食性、高温クリープ強度、加工性を満足するＮｉ−１８．５％Ｃｒ−２１％Ｗを骨格組成とすることとし、Ｃｒの含有量の範囲を１７〜２０％とした。
【００１１】
ＷはＮｉ−Ｃｒ−Ｗ系合金において、固溶強化とα2相の析出によりクリープ強度を高める重要な元素である。そのため、ＣｒとＷの和はα2相析出領域である３９〜４３％に限定した。Ｗは上記のＣｒの組成範囲とα2相析出領域を考慮し、その含有量を２０〜２３％とした。
【００１２】
ＴｉはＮｉ−Ｃｒ−Ｗ系合金において、溶接割れ感受性を低くする有益な元素である。上記効果を得るためには、０．０２％以上の添加が必要である。しかし、過剰添加は溶接割れ感受性の低減効果を少なくし、耐食性を劣化させるため、上限を０．１％とし、Ｔｉの含有量を０．０２〜０．１％と定めた。
【００１３】
Ｚｒは熱間加工性を向上させる元素であり、高温クリープ強度の向上に寄与する元素である。しかしながら、Ｚｒは溶接高温割れを助長する元素であり、
０．０３％を超えて添加すると溶接割れ感受性が高まり、溶接金属において割れの原因とされるＺｒ富化相が検出された。よってＺｒは０．０３％以下を含有することとした。このＺｒ含有量の上限値は、後に述べる溶接割れ感受性指数からの制限（１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙ≦０．３％）を他の元素が共存しないとして、Ｚｒのみにあてはめた場合の値でもある。
【００１４】
Ｙは耐食性を向上させる上で重要な元素であり、熱間加工性の向上にも役立つが、添加量が０．０１５％を超えるとクリープ強度及び溶接性を低下させる。そのため、Ｙは０．０１５％以下を含有することとした。
【００１５】
ＢはＺｒと同様に熱間加工性を向上させる元素であり、高温クリープ強度の向上にも寄与する元素である。上記効果はＢ量０．０００２％ではやや不十分で、０．０００３％以上Ｂを含有することで効果が大きい。しかしながら、Ｂは低融点の化合物を作るため、Ｂを０．０１％以上添加すると溶接割れを助長する。そのため、Ｂの含有量を０．０００３〜０．０１％と定めた。
【００１６】
Ｍｇは脱酸、脱硫作用があり、溶加材に微量含有することにより、溶接割れ感受性が低下するが、溶接金属中に０．０５％を超えて過剰に含有すると溶接割れ感受性は著しく高くなる。よって、Ｍｇは０．０５％以下を含有することとした。好ましい含有量は０．０００１〜０．０５％である。
【００１７】
Ａｌは合金の溶製時に脱酸作用があるが、粒界酸化によって耐食性を低下させる。そのため、Ａｌの含有量は母材と同様の０．１％以下とした。
Ｎｂは溶接割れ感受性を高める元素であり、耐食性も低下させる。このため、その含有量を０．０６％以下とした。このＮｂ合有量の上限値は、以下に述べる溶接割れ感受性指数からの制限（１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙ≦０．３％）を他の元素が共存しないとして、Ｎｂのみにあてはめた場合の値である。
【００１８】
本発明の特徴は、この合金系において、溶接割れ感受性を著しく高めるＺｒ、Ｂ、Ｎｂ、Ｙについて、溶接割れ感受性指数を定めたことにある。すなわち、
Ｚｒ、Ｂ、Ｎｂ、Ｙについては、それらの元素の割れ感受性を高める程度により係数を決め、複合効果を考慮して、溶接割れ感受性指数を１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙと定めた。この溶接割れ感受性指数の値が０．３％以下となるようにすることにより、この合金系について、溶接性の優れた溶加材を製造することができる。
【００１９】
【実施例】
以下、本発明の実施例を比較例と対比させて説明する。表１は、供試材の化学成分を示す。Ａ１〜Ａ６は本発明合金、Ｂ１〜Ｂ１５は比較例である。これらの合金を用いて、表２および表３に示す溶接条件でタングステン・イナートガス（ＴＩＧ）の溶接による溶接性試験を行った。表２は手動ＴＩＧの場合の条件、表３は自動ＴＩＧ溶接の場合の条件である。
【００２０】
【表１】
（その１）
【表１】
（その２）
【表２】
【表３】
Ａ１、Ａ２、Ｂ１〜Ｂ１３については、断面が３（ｍｍ）×３（ｍｍ）の角材を溶加材に用い、手動ＴＩＧ溶接によって、残りのＡ３〜Ａ６、Ｂ１４、Ｂ１５については、φ１．２（ｍｍ）までに加工した溶接用ワイヤーを溶加材に用い、自動ＴＩＧ溶接によって溶接性試験を実施した。
【００２５】
溶加材の溶接性は、Ｃ型ジグ拘束突き合わせ溶接割れ試験（以下、ＦＩＳＣＯ試験）、肉盛溶接による溶接割れ感受性試験、溶接継手の曲げ試験および溶接金属のミクロ組織試験により総合的に評価した。肉盛溶接による溶接割れ感受性試験では、肉盛溶接後に溶接金属部の表面を約４ｍｍ切除し、再熱を受けた肉盛溶接部を液体浸透試験により、溶接割れの有無を調べた。
【００２６】
Ａ１合金は、溶接性試験および溶接部のクリープ試験片を作製するときの母材としても使用した。溶接性の優れていた合金のうち、Ａ２〜Ａ６、Ｂ１４を溶加材に用いて、ＴＩＧ溶接により、Ａ１合金を母材として、溶接継手を作製し、クリープ試験用の試験片を作製した。クリープ試験には、直径６ｍｍ、標点間距離３０ｍｍの試験片を用いた。Ａ２合金は標点間に母材と溶接金属両方を含む溶接継手試験片、Ａ３合金では溶接継手試験片と試験片が溶接金属のみからなる溶接金属試験片、Ａ４、Ａ５、Ａ６、Ｂ１４合金では溶接金属試験片を使用した。クリープ試験では、１０００℃、２９．４ＭＰａの条件で試験を行った。評価の判断は、母材の破断時間の８０％以上を合格とし、これに達しないものをクリープ強度不足とした。
【００２７】
表４は溶接性および溶接部のクリープ強度の評価結果である。溶接性試験の〇印は溶接性良好、×印は溶接性不良を示す。クリープ強度の評価結果では、〇印を強度十分、×印を強度不足で表し、溶接部の破断時間の母材に対する比も示した。
【００２８】
【表４】
表１で、比較例において、成分組成および溶接割れ感受性指数で本発明の範囲外の値は＊印で示した。溶接割れ感受性指数の算出において、含有量の少ない元素で分析値が検出感度未満となっているものについては、検出感度の値を用いて計算した。表４の評価結果に示したように、本発明の合金は、溶接性試験において溶接割れが発生せず溶接性が良好であり、溶接部のクリープ強度は溶接継手、溶接金属とも十分である。これに対し、比較例の合金は溶接性不良あるいはクリープ強度不足である。
【００３０】
図１に本発明合金Ａ６のＦＩＳＣＯ試験の結果を示す。本発明合金Ａ６はクレーター割れのみであり、ビード割れは発生していないため、溶接割れ感受性は低い。図２は比較例の溶接合金Ｂ２のＦＩＳＣＯ試験の結果であり、著しいビード割れが発生している。図３に本発明合金Ａ６の肉盛溶接後の液体浸透試験の結果を示す。本発明合金Ａ６の液体浸透試験では溶接割れは観察されない。これに対して、比較例の溶接合金Ｂ２の結果である図４では、著しい溶接高温割れが観察される。図５は本発明合金Ａ１の溶接継手の曲げ試験の結果であり、この合金の溶接継手は１８０°まで曲げることができ、溶接性は優れている。図６に示した比較合金Ｂ１３の溶接継手の曲げ試験では、溶接継手は１８０°まで曲がることなく溶接部で破断した。図７は本発明合金Ａ１の溶接金属のミクロ組織試験の結果であり、割れは観察されない。これに対して、図８に示した比較合金Ｂ４の結果では、溶接金属の粒界部に著しい割れが認められる。
【００３１】
溶接性が不良であった表４の比較例Ｂ１〜Ｂ１３は、表１に示すように、溶接割れ感受性の指標である１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙの値が０．３％を越えている。さらに、Ｂ１は溶接高温割れを抑えるＴｉの量が０．００２％と低く、Ｂ２は溶接割れ感受性を高めるＺｒが０．０４１％と高い。Ｂ３はＴｉの量が０．２％と高く、Ｂ９はＺｒの量が０．０４％と高く、溶接割れを起こしている。Ｂ１〜Ｂ１３の合金については、溶接性が劣り、溶接割れが発生したため、溶接部のクリープ強度評価ができなかった。
【００３２】
比較例のＢ１４およびＢ１５については、溶接割れ感受性の指標である１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙの値が０．３％以下であり、溶接高温割れも発生しなかった。Ｂ１４は溶接性は良好であったが、Ｂ量が０．０００２％と低く、クリープ強度を高めるＺｒ量も低めであることから、クリープ試験における溶接部の破断時間の母材に対する比が０．６８と低下した。
【００３３】
【発明の効果】
本発明のＮｉ−Ｃｒ−Ｗ系合金の溶接用溶加材は、特公平５−４７６１２で発明したＮｉ−Ｃｒ−Ｗ系超耐熱合金のうち、Ｃｒ量１７〜２０％、Ｗ量２０〜２３％の母材合金に対して、溶接ワイヤーに加工が可能で溶接性に優れ、かつ母材に匹敵する優れた高温クリープ強度を有する溶接部を作製することを可能とする。従って、１０００℃付近の高温で使用される溶接構造物に適用される。
【図面の簡単な説明】
【図１】本発明合金Ａ６のＦＩＳＣＯ試験の結果である。
【図２】比較合金Ｂ２のＦＩＳＯＯ試験の結果である。
【図３】本発明合金Ａ６の肉盛溶接後の液体浸透試験の結果である。
【図４】比較合金Ｂ２の肉盛溶接後の液体浸透試験の結果である。
【図５】本発明合金Ａ１の溶接継手の曲げ試験の結果である。
【図６】比較合金Ｂ１３の溶接継手の曲げ試験の結果である。
【図７】本発明合金Ａ１の溶接金属のミクロ組織試験の結果である。
【図８】比較合金Ｂ４の溶接金属のミクロ組織試験の結果である。[0001]
[Industrial application fields]
The present invention relates to a filler metal for welding of a Ni—Cr—W alloy having excellent high temperature strength and corrosion resistance used in a high temperature gas furnace high temperature structure, a gas turbine, and the like.
[0002]
[Prior art]
Conventionally, Ni—Cr—W alloys, Ni—Cr—W—Mo alloys, and the like have been developed as super heat resistant materials used in high temperature gas furnace high temperature structures, gas turbines, and the like. Since these alloys are used at a high temperature around 1000 ° C., they are required to have excellent high-temperature creep strength and corrosion resistance.
[0003]
In view of such demands, for example, Ni—Cr alloys reinforced with W or Mo have been proposed as disclosed in JP-A-51-29316, JP-B-54-33212, and JP-B-5-47612. In order to manufacture a structure using these alloys, welding is used. Further, since such a structure is used at a high temperature for a long time, a high temperature creep strength is also required for the welded portion.
[0004]
Japanese Patent Application Laid-Open No. 51-29316 discloses a heat-resistant alloy for welding for making a welded structure made of a Ni—Cr—W alloy or a Ni—Cr—W—Mo alloy. For 20% of the alloy, the composition range is kept so as not to cause weld cracking. NI-Cr-W alloys are very susceptible to weld cracking, and when an alloy with the exact same chemical composition as the base metal is used as the filler metal, it is difficult to create a welded structure with weld cracking. It is. In addition, it is important to ensure the high-temperature structure soundness that the high-temperature creep strength of the welded part is as high as that of the base metal, but in the case of Ni-Cr-W alloy, it can be processed into a welding wire However, it has not yet been possible to develop a filler metal having excellent weldability and high-temperature creep strength of the welded portion as well as that of the base material.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to provide excellent hot workability to a Ni-Cr-W alloy with high weld crack sensitivity, and can be processed into a wire, and also has excellent weldability and high temperature creep strength of a welded portion. Is to provide a welding filler metal that is as excellent as the base metal.
[0006]
[Means for Solving the Problems]
In the present invention, C: 0.05% or less, Mn: 0.1% or less, Si: 0.1% or less (provided that Mn + Si = 0.1% or less)
Cr: 17-20%
W: 20-23%
(However, Cr + W = 39-43%)
Ti: 0.02 to 0.1%
Zr: 0.03% or less Y: 0.015% or less B: 0.0003 to 0.01%
Al: 0.1% or less Mg: 0.05% or less Nb: 0.06% or less (however, 10Zr + 10B + 5Nb + 2Y = 0.3% or less)
Is a filler material for welding a Ni—Cr—W alloy having a composition (more than mass%) consisting of Ni and inevitable impurities.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The filler metal for welding of the present invention is a base metal alloy having a Ni-18.5% Cr-21% W alloy as a skeleton composition among the Ni-Cr-W based superalloys invented in Japanese Patent Publication No. 5-47612. On the other hand, by adjusting the amount of the trace element contained in the alloy, it can be processed into a welding wire and has excellent weldability, and the high temperature creep strength of the welded portion can be made comparable to that of the base material. The reasons for adding each component and the reasons for limiting the composition of the filler metal for welding of the present invention will be described below.
[0008]
C is an element that improves hot workability in producing an alloy, and is generally an element that improves high-temperature creep strength. However, since the use temperature is high in the Ni—Cr—W alloy, the creep strength does not depend much on the amount of C, and the C may move out of the alloy during use. Further, when the amount of C is large, aging embrittlement sensitivity is increased due to precipitation of brittle carbides. Therefore, the amount of C is kept low and 0.05% or less is contained. A preferable content is 0.01 to 0.04%.
[0009]
Mn and Si have a deoxidizing action when the alloy is melted, and are effective in improving corrosion resistance, but reduce hot workability and creep strength. In order to ensure hot workability and creep strength in Ni—Cr—W alloys, both Mn and Si alone are 0.1% or less, and if both elements are present simultaneously, the sum is 0.1%. Limited to:
[0010]
Cr is necessary for securing the corrosion resistance and high temperature creep strength of the weld metal, but if added excessively, the workability to the welding wire is impaired. In the present invention, among the base metal alloy having a Cr amount of 16 to 28% invented in Japanese Patent Publication No. 5-47612, Ni-18.5% Cr-21% W satisfying corrosion resistance, high temperature creep strength and workability is used as a skeleton composition. And the Cr content range was 17 to 20%.
[0011]
W is an important element for increasing the creep strength by solid solution strengthening and precipitation of α 2 phase in the Ni—Cr—W alloy. Therefore, the sum of Cr and W is limited to 39 to 43%, which is the α 2 phase precipitation region. Considering the Cr composition range and the α 2 phase precipitation region, the content of W is set to 20 to 23%.
[0012]
Ti is a beneficial element that lowers weld cracking susceptibility in Ni—Cr—W alloys. In order to acquire the said effect, 0.02% or more needs to be added. However, excessive addition reduces the weld crack sensitivity reduction effect and degrades the corrosion resistance. Therefore, the upper limit was set to 0.1%, and the Ti content was determined to be 0.02 to 0.1%.
[0013]
Zr is an element that improves hot workability and is an element that contributes to the improvement of high-temperature creep strength. However, Zr is an element that promotes weld hot cracking,
When added over 0.03%, the sensitivity to weld cracking increased, and a Zr-enriched phase, which is the cause of cracking in the weld metal, was detected. Therefore, Zr is determined to contain 0.03% or less. This upper limit of the Zr content is also a value when the limit from the weld crack sensitivity index described later (10Zr + 10B + 5Nb + 2Y ≦ 0.3%) is applied only to Zr, assuming that other elements do not coexist.
[0014]
Y is an important element for improving the corrosion resistance and helps to improve the hot workability. However, if the added amount exceeds 0.015%, the creep strength and weldability are lowered. Therefore, Y is determined to contain 0.015% or less.
[0015]
B, like Zr, is an element that improves hot workability, and is an element that also contributes to improvement of high temperature creep strength. The above effect is somewhat insufficient when the B amount is 0.0002%, and the effect is large when B is contained by 0.0003% or more. However, since B forms a low melting point compound, the addition of 0.01% or more of B promotes weld cracking. Therefore, the B content is determined to be 0.0003 to 0.01%.
[0016]
Mg has a deoxidation and desulfurization action, and if contained in a small amount in the filler metal, the weld cracking sensitivity decreases, but if it exceeds 0.05% in the weld metal, the weld cracking sensitivity becomes remarkably high. . Therefore, Mg is determined to contain 0.05% or less. A preferable content is 0.0001 to 0.05%.
[0017]
Al has a deoxidizing action when the alloy is melted, but reduces the corrosion resistance by grain boundary oxidation. Therefore, the Al content is set to 0.1% or less, which is the same as that of the base material.
Nb is an element that increases the sensitivity to weld cracking, and also reduces corrosion resistance. For this reason, the content was made 0.06% or less. This upper limit value of the Nb content is a value obtained when the following limit (10Zr + 10B + 5Nb + 2Y ≦ 0.3%) from the weld crack sensitivity index is applied only to Nb, assuming that other elements do not coexist.
[0018]
The feature of the present invention is that a weld cracking sensitivity index is determined for Zr, B, Nb, and Y that remarkably increase the weld cracking sensitivity in this alloy system. That is,
For Zr, B, Nb, and Y, coefficients were determined depending on the degree to which the crack susceptibility of these elements was increased, and the weld crack susceptibility index was determined to be 10Zr + 10B + 5Nb + 2Y in consideration of the composite effect. By making the value of this weld crack susceptibility index to be 0.3% or less, a filler material having excellent weldability can be produced for this alloy system.
[0019]
【Example】
Examples of the present invention will be described below in comparison with comparative examples. Table 1 shows the chemical components of the test materials. A1 to A6 are the alloys of the present invention, and B1 to B15 are comparative examples. Using these alloys, a weldability test by welding with tungsten inert gas (TIG) was performed under the welding conditions shown in Tables 2 and 3. Table 2 shows conditions for manual TIG, and Table 3 shows conditions for automatic TIG welding.
[0020]
[Table 1]
(Part 1)
[Table 1]
(Part 2)
[Table 2]
[Table 3]
For A1, A2, B1 to B13, a cross section of 3 (mm) × 3 (mm) is used as the filler metal, and the remaining A3 to A6, B14, and B15 are φ1.2 by manual TIG welding. A welding wire processed by (mm) was used as a filler metal, and a weldability test was performed by automatic TIG welding.
[0025]
The weldability of the filler metal was comprehensively evaluated by a C-type jig restraint butt welding crack test (hereinafter referred to as FISCO test), weld crack sensitivity test by overlay welding, bending test of welded joint, and microstructure test of weld metal. . In the weld crack susceptibility test by overlay welding, the surface of the weld metal part was excised by about 4 mm after overlay welding, and the weld weld part subjected to reheating was examined for the presence of weld cracks by a liquid penetration test.
[0026]
The A1 alloy was also used as a base material for producing a weldability test and a creep test piece of a weld. Among the alloys having excellent weldability, A2 to A6 and B14 were used as filler materials, and TIG welding was used to produce a welded joint using A1 alloy as a base material, thereby producing a specimen for a creep test. For the creep test, a test piece having a diameter of 6 mm and a distance between gauge points of 30 mm was used. A2 alloy is a welded joint test piece including both the base metal and the weld metal between the gauge marks, A3 alloy is a welded joint test piece and the weld metal test piece is composed of only weld metal, and A4, A5, A6, B14 alloy A weld metal specimen was used. In the creep test, the test was performed at 1000 ° C. and 29.4 MPa. In the judgment of evaluation, 80% or more of the fracture time of the base material was regarded as acceptable, and those not reaching this were regarded as insufficient creep strength.
[0027]
Table 4 shows the evaluation results of weldability and creep strength of the weld. In the weldability test, ◯ indicates good weldability, and x indicates poor weldability. In the evaluation results of the creep strength, the symbol “◯” indicates that the strength is sufficient, the symbol “×” indicates that the strength is insufficient, and the ratio of the fracture time of the weld to the base material is also shown.
[0028]
[Table 4]
In Table 1, in the comparative examples, values outside the range of the present invention in terms of component composition and weld cracking sensitivity index are indicated by *. In the calculation of the weld crack sensitivity index, an element having a small content and an analytical value less than the detection sensitivity was calculated using the value of the detection sensitivity. As shown in the evaluation results of Table 4, the alloy of the present invention does not generate weld cracks in the weldability test and has good weldability, and the weld joint has sufficient creep strength for both the welded joint and the weld metal. In contrast, the alloy of the comparative example has poor weldability or insufficient creep strength.
[0030]
FIG. 1 shows the result of the FISCO test of the alloy A6 of the present invention. The alloy A6 of the present invention has only crater cracks and no bead cracks, so the weld crack sensitivity is low. FIG. 2 shows the result of the FISCO test of the welding alloy B2 of the comparative example, and significant bead cracking occurs. FIG. 3 shows the result of the liquid penetration test after overlay welding of the alloy A6 of the present invention. No weld cracking is observed in the liquid penetration test of the alloy A6 of the present invention. On the other hand, remarkable welding hot cracking is observed in FIG. 4 which is the result of the welding alloy B2 of the comparative example. FIG. 5 shows the results of a bending test of the welded joint of the alloy A1 of the present invention. The welded joint of this alloy can be bent up to 180 °, and the weldability is excellent. In the bending test of the welded joint of comparative alloy B13 shown in FIG. 6, the welded joint was broken at the welded portion without bending up to 180 °. FIG. 7 shows the result of the microstructure test of the weld metal of the alloy A1 of the present invention, and no cracks are observed. On the other hand, in the result of the comparative alloy B4 shown in FIG. 8, remarkable cracks are observed in the grain boundary part of the weld metal.
[0031]
As shown in Table 1, in Comparative Examples B1 to B13 in Table 4 in which the weldability was poor, the value of 10Zr + 10B + 5Nb + 2Y, which is an index of weld crack sensitivity, exceeded 0.3%. Further, B1 has a low amount of Ti that suppresses weld hot cracking as low as 0.002%, and B2 has a high Zr of 0.041% that enhances weld crack sensitivity. B3 has a high Ti content of 0.2%, and B9 has a high Zr content of 0.04%, causing weld cracking. Regarding the alloys B1 to B13, weldability was poor and weld cracking occurred, so that the creep strength of the welded portion could not be evaluated.
[0032]
For Comparative Examples B14 and B15, the value of 10Zr + 10B + 5Nb + 2Y, which is an index of weld cracking sensitivity, was 0.3% or less, and no weld hot cracking occurred. Although the weldability of B14 was good, the B content was as low as 0.0002%, and the Zr content that increases the creep strength was also low, so the ratio of the fracture time of the welded portion in the creep test to the base metal was 0. It decreased to 68.
[0033]
【The invention's effect】
The welding material for welding of the Ni—Cr—W alloy of the present invention is a Cr amount of 17-20% and a W amount of 20-23 of the Ni—Cr—W super heat resistant alloy invented in Japanese Patent Publication No. 5-47612. % Of the base metal alloy can be processed into a welding wire, has excellent weldability, and can produce a weld having excellent high temperature creep strength comparable to that of the base metal. Therefore, it is applied to a welded structure used at a high temperature around 1000 ° C.
[Brief description of the drawings]
FIG. 1 is a result of a FISCO test of an alloy A6 of the present invention.
FIG. 2 is a result of FISOO test of comparative alloy B2.
FIG. 3 is a result of a liquid penetration test after overlay welding of an alloy A6 of the present invention.
FIG. 4 is a result of a liquid penetration test after build-up welding of comparative alloy B2.
FIG. 5 is a result of a bending test of a welded joint of the alloy A1 of the present invention.
FIG. 6 is a result of a bending test of a welded joint of comparative alloy B13.
FIG. 7 is a result of a microstructure test of a weld metal of the alloy A1 of the present invention.
FIG. 8 is a result of a microstructure test of a weld metal of comparative alloy B4.
Claims (1)
Ｍｎ：０．１％以下
Ｓｉ：０．１％以下
（ただし、Ｍｎ＋Ｓｉ＝０．１％以下）
Ｃｒ：１７〜２０％
Ｗ ：２０〜２３％
（ただし、Ｃｒ＋Ｗ＝３９〜４３％）
Ｔｉ：０．０２〜０．１％
Ｚｒ：０．０３％以下
Ｙ ：０．０１５％以下
Ｂ ：０．０００３〜０．０１％
Ａｌ：０．１％以下
Ｍｇ：０．０５％以下
Ｎｂ：０．０６％以下
（ただし、１０Ｚｒ＋１０Ｂ＋５Ｎｂ＋２Ｙ＝０．３％以下）
を含有し、残りがＮｉおよび不可避不純物からなる組成（以上、質量％）を有するＮｉ−Ｃｒ−Ｗ系合金の溶接用溶加材。C: 0.05% or less Mn: 0.1% or less Si: 0.1% or less (however, Mn + Si = 0.1% or less)
Cr: 17-20%
W: 20-23%
(However, Cr + W = 39-43%)
Ti: 0.02 to 0.1%
Zr: 0.03% or less Y: 0.015% or less B: 0.0003 to 0.01%
Al: 0.1% or less Mg: 0.05% or less Nb: 0.06% or less (however, 10Zr + 10B + 5Nb + 2Y = 0.3% or less)
A filler material for welding of a Ni—Cr—W alloy having a composition (more than mass%) consisting of Ni and the remainder consisting of Ni and inevitable impurities.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14211699A JP4395583B2 (en) | 1999-05-21 | 1999-05-21 | Ni-Cr-W alloy alloy filler metal for welding |
| US09/714,981 US6521060B1 (en) | 1999-05-21 | 2000-11-20 | Filler metal for use in welding of Ni-Cr-W alloys |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14211699A JP4395583B2 (en) | 1999-05-21 | 1999-05-21 | Ni-Cr-W alloy alloy filler metal for welding |
| US09/714,981 US6521060B1 (en) | 1999-05-21 | 2000-11-20 | Filler metal for use in welding of Ni-Cr-W alloys |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000326089A JP2000326089A (en) | 2000-11-28 |
| JP4395583B2 true JP4395583B2 (en) | 2010-01-13 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14211699A Expired - Fee Related JP4395583B2 (en) | 1999-05-21 | 1999-05-21 | Ni-Cr-W alloy alloy filler metal for welding |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US6521060B1 (en) |
| JP (1) | JP4395583B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8669491B2 (en) * | 2006-02-16 | 2014-03-11 | Ravi Menon | Hard-facing alloys having improved crack resistance |
| US20100101780A1 (en) * | 2006-02-16 | 2010-04-29 | Michael Drew Ballew | Process of applying hard-facing alloys having improved crack resistance and tools manufactured therefrom |
| KR101197990B1 (en) | 2010-11-12 | 2012-11-05 | 가부시키가이샤 고베 세이코쇼 | Ni BASE ALLOY SOLID WIRE FOR WELDING |
| US8765052B2 (en) | 2012-03-27 | 2014-07-01 | Stoody Company | Abrasion and corrosion resistant alloy and hardfacing/cladding applications |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5129316A (en) | 1974-09-06 | 1976-03-12 | Nippon Steel Corp | |
| JPS5433212A (en) | 1977-08-19 | 1979-03-10 | Kawasaki Heavy Ind Ltd | Preventing apparatus for dew condensation in exhaust gas from industrial furnace |
| US5449490A (en) * | 1988-12-27 | 1995-09-12 | Japan Atomic Energy Research Institute | Nickel-chromium-tungsten base superalloy |
| JP3135072B2 (en) | 1991-08-12 | 2001-02-13 | 日本カーリット株式会社 | Method for manufacturing solid electrolytic capacitor |
-
1999
- 1999-05-21 JP JP14211699A patent/JP4395583B2/en not_active Expired - Fee Related
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2000
- 2000-11-20 US US09/714,981 patent/US6521060B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000326089A (en) | 2000-11-28 |
| US6521060B1 (en) | 2003-02-18 |
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